Home position sensor system for positioning print carriage and method thereof

Abstract

A home position sensor system and method capable of shortening the amount of time consumed for sensing a home position. The home position sensor system including a carriage wherein a recording head is mounted and being movable in a horizontal direction, two sensing ribs separated by a constant interval from each other along the moving direction of the carriage and protrudedly formed in the carriage, a home sensor provided at one side cad of a moving path of the carriage to thereby correspond to the sensing ribs, a carriage driver for moving the carriage, and a controller for moving the carriage in a horizontal direction through the carriage driver in accordance with sensing states of the home sensor to the two sensing ribs to thereby sense a home position.

What is claimed is: 
     
       1. A printing apparatus, comprising: a printer frame;   a carriage movably mounted on said printer frame and having a recording head mounted thereon, for printing onto a recording medium, said carriage being movable in a predetermined axis relative to said recording medium;   a first sensing rib and a second sensing rib separately mounted on said carriage along said predetermined axis relative to said recording medium;   a home sensor mounted on said printer frame at one end of said predetermined axis, for sensing whether said carriage passes through a home position representing an initial reference position for enabling said recording head mounted on said carriage to begin printing on said recording medium along said predetermined axis;   a carriage driver for driving said carriage to move along said predetermined axis relative to said recording medium; and   a controller for controlling the movement of said carriage along said predetermined axis to position said carriage at said home position upon initialization for enabling printing on said recording medium, said controller controlling said carriage driver to move said carriage at high speed in a direction toward said home position until detection of a first one of said first sensing rib and said second sensing rib by said home sensor, and then to move said carriage at low speed in the direction toward said home position until detection of a second one of said first sensing rib and said second sensing rib by said home sensor.   
     
     
       2. The printing apparatus of claim 1, further comprised of said second sensing rib serving as a reference sensing rib so that, when said second sensing rib is sensed by said home sensor as said second sensing rib mounted on said carriage passes through said home sensor, said home sensor determines that said carriage is at said home position for enabling said recording head to begin printing on said recording medium along said predetermined axis. 
     
     
       3. The printing apparatus of claim 1, further comprised of said home sensor comprising a base portion, a light emitting portion and a light receiving portion extending in parallel from said base portion, said light emitting portion emitting a light to be received by said light receiving portion when neither said first sensing rib nor said second sensing rib separately mounted on said carriage passes through said light emitting portion and said light receiving portion indicating that said home sensor is turned "off." 
     
     
       4. The printing apparatus of claim 3, further comprised of said home sensor tuning "on" when any one of said first sensing rib and said second sensing rib separately mounted on said carriage passes through said light emitting portion and said light receiving portion. 
     
     
       5. The printing apparatus of claim 1, further comprised of said controller moving said carriage along said predetermined axis until a first one of said first sensing rib and second sensing rib is detected by said home sensor, moving said carriage by a first distance in the direction away from said home position and determining whether a second one of said first sensing rib and said second sensing rib is detected by said home sensor, and when said second one of said first sensing rib and said second sensing rib is detected by said home sensor, moving said carriage by said first distance in the direction toward said home position to position said carriage at said home position to begin printing on said recording medium along said predetermined axis. 
     
     
       6. The printing apparatus of claim 5, further comprised of said controller controlling the movement of said carriage by: determining whether said first one of said first sensing rib and said second sensing rib is detected by said home sensor;   moving said carriage in the direction toward said home position while determining whether said first one of said first sensing rib and said second sensing rib is detected by said home sensor, when said first one of said first sensing rib and said second sensing rib is not detected by said home sensor;   determining whether said carriage has moved by a second distance, when neither said first sensing rib nor said second sensing rib is detected by said home sensor;   moving said carriage at high speed in the direction toward said home position until said first one of said first sensing rib and said second sensing rib is detected by said home sensor;   when said first one of said first sensing rib and said second sensing rib is detected by said home sensor, moving said carriage at low speed in the direction toward said home position until said second one of said first sensing rib and said second sensing rib is detected by said home sensor; and   positioning said carriage at said home position to begin printing on said recording medium along said predetermined axis.   
     
     
       7. The printing apparatus of claim 6, further comprised of said controller moving said carriage by said second distance in the direction away from said home position, when said first one of said first sensing rib and said second sensing rib is detected by said home sensor while said carriage is moving in the direction toward said home position, and moving said carriage back in the direction toward said home position until both said first sensing rib and said second sensing rib are sequentially detected by said home sensor so as to position said carriage at said home position to begin printing on said recording medium along said predetermined axis. 
     
     
       8. The printing apparatus of claim 7, further comprised of said first distance corresponding to a predetermined spacing between said first sensing rib and said second sensing rib separately mounted on said carriage, and said second distance corresponding to twice said first distance. 
     
     
       9. A printing apparatus, comprising: a carriage movably mounted on a printer frame and having a recording head mounted thereon for printing onto a recording medium, said carriage being movable in a predetermined axis relative to said recording medium;   first and second sensing ribs separately mounted on said carriage along said predetermined axis relative to said recording medium;   a home sensor mounted on said printer frame at one end of said predetermined axis, for sensing whether said carriage passes through a home position representing an initial reference position for enabling said recording head mounted on said carriage to begin printing on said recording medium along said predetermined axis;   a carriage driver for driving said carriage to move along said predetermined axis relative to said recording medium; and   a controller for controlling the movement of said carriage along said predetermined axis at one of high speed and low speed to position said carriage at said home position upon initialization in dependence upon detection of said first sensing rib and said second sensing rib by said home sensor.   
     
     
       10. The printing apparatus of claim 9, further comprised of said second sensing rib serving as a reference sensing rib so that, when said second sensing rib is sensed by said home sensor as said second sensing rib mounted on said carriage passes through said home sensor, said home sensor determines that said carriage is at said home position for enabling said recording head to begin printing on said recording medium along said predetermined axis. 
     
     
       11. The printing apparatus of claim 10, further comprised of said home sensor comprising a base portion, a light emitting portion and a light receiving portion extending in parallel from said base portion, said light emitting portion emitting a light to be received by said light receiving portion when neither said first sensing rib nor said second sensing rib separately mounted on said carriage passes through said light emitting portion and said light receiving portion indicating that said home sensor is turned "off." 
     
     
       12. The printing apparatus of claim 11, further comprised of said home sensor turning "on" when any one of said first sensing rib and said second sensing rib separately mounted on said carriage passes through said light emitting portion and said light receiving portion. 
     
     
       13. The printing apparatus of claim 9, further comprised of said controller moving said carriage along said predetermined axis until a first one of said first sensing rib and said second sensing rib is detected by said home sensor, moving said carriage by a first distance in the direction away from said home position and determining whether a second one of said first sensing rib and said second sensing rib is detected by said home sensor, and when said second one of said first sensing rib and said second sensing rib is detected by said home sensor, moving said carriage by said first distance in the direction toward said home position to position said carriage at said home position to begin printing on said recording medium along said predetermined axis. 
     
     
       14. The printing apparatus of claim 9, further comprised of said controller controlling the movement of said carriage by: determining whether a first one of said first sensing rib and said second sensing rib is detected by said home sensor;   moving said carriage in the direction toward said home position while determining whether said first one of said first sensing rib and said second sensing rib is detected by said home sensor, when said first one of said first sensing rib and said second sensing rib is not detected by said home sensor;   determining whether said carriage has moved by a second distance, when neither said first sensing rib nor said second sensing rib is detected by said home sensor;   moving said carriage at high speed in the direction toward said home position until said first one of said first sensing rib and said second sensing rib is detected by said home sensor;   when said first one of said first sensing rib and said second sensing rib is detected by said home sensor, moving said carriage at low speed in the direction toward said home position until a second one of said first sensing rib and said second sensing rib is detected by said home sensor; and   positioning said carriage at said home position to begin printing on said recording medium along said predetermined axis.   
     
     
       15. The printing apparatus of claim 14, further comprised of said controller moving said carriage by said second distance in the direction away from said home position, when said first one of said first sensing rib and said second sensing rib is detected by said home sensor while said carriage is moving in the direction toward said home position, and moving said carriage back in the direction toward said home position until both said first sensing rib and said second sensing rib are sequentially detected by said home sensor so as to position said carriage at said home position to begin printing on said recording medium along said predetermined axis. 
     
     
       16. The printing apparatus of claim 9, further comprised of said controller moving said carriage in the direction toward said home position to determine whether said first and second sensing ribs are detected by said home sensor, and when neither said first sensing rib nor said second sensing rib is detected by said home sensor, determining that said recording head is not mounted on said carriage. 
     
     
       17. The printing apparatus of claim 15, further comprised of said first distance corresponding to a predetermined spacing between said first sensing rib and said second sensing rib separately mounted on said carriage, and said second distance corresponding to twice said first distance. 
     
     
       18. A home position sensing method of a printer comprising a carriage having a recording head a first sensing rib and a second sensing rib separately mounted on said carriage, and a home sensor for sensing whether said carriage passes through a home position to enable said recording head to begin printing on a recording medium, said method comprising the steps of: determining whether a first one of said first sensing rib and said second sensing rib is detected by said home sensor;   when said first one of said first sensing rib and said second sensing rib is detected by said home sensor, moving said carriage at low speed by a first distance in a direction away from said home position;   determining whether a second one of said first sensing rib and said second sensing rib   when said second one of said first sensing rib and said second sensing rib is not detected by said home sensor, moving said carriage at low speed in a direction toward said home position until said first sensing rib and said second sensing rib are sequentially detected by said home sensor to position said carriage at said home position to begin printing on said recording medium along a predetermined axis; and   when said second one of said first sensing rib and said second sensing rib is detected by said home sensor, moving said carriage at low speed by said first distance in the direction toward said home position to position said carriage at said home position to begin printing on said recording medium along said predetermined axis.   
     
     
       19. The home position sensing method of claim 18, further comprising: when said first one of said first sensing rib and said second sensing rib is not detected by said home sensor, moving said carriage at low speed in the direction toward said home position while determining whether said first one of said first sensing rib and a second sensing rib is detected by said home sensor;   determining whether said carriage has moved by a second distance, when neither said first sensing rib nor said second sensing rib is detected by said home sensor;   moving said carriage at high speed in the direction toward said home position until said first one of said first sensing rib and said second sensing rib is detected by said home sensor;   when said first one of said first sensing rib and said second sensing rib is detected by said home sensor, moving said carriage at low speed in the direction toward said home position until said second one of said first sensing rib and said second sensing rib is detected by said home sensor; and   positioning said carriage at said home position to begin printing on said recording medium along said predetermined axis.   
     
     
       20. The home position sensing method of claim 19, further comprising: moving said carriage at low speed by said second distance in the direction away from said home position, when said first one of said first sensing rib and said second sensing rib is detected by said home sensor while said carriage moves at low speed in the direction toward said home position; and   moving said carriage at low speed in the direction toward said home position until both said first sensing rib and said second sensing rib are sequentially detected by said home sensor so as to position said carriage at said home position to begin printing on said recording medium along said predetermined axis.   
     
     
       21. The home position sensing method of claim 20, further comprised of said first distance corresponding to a predetermined spacing between said first sensing rib and said second sensing rib separately mounted on said carriage. 
     
     
       22. The home position sensing method of claim 21, further comprised of said second distance corresponding to twice said first distance. 
     
     
       23. A process of positioning a carriage of a printer at a home position upon initialization, comprising the steps of: moving said carriage having a first sensing rib and a second sensing rib separately mounted thereon, at high speed in a direction toward a home position serving as a starting position for beginning printing information on a recording medium until a first one of said first sensing rib and said second sensing rib passes through said home position;   when said first one of said first sensing rib and said second sensing rib passes through said home position, moving said carriage at low speed in the direction toward said home position until a second one of said first sensing rib and said second sensing rib passes through said home position; and   positioning said carriage at said home position to begin printing on said recording medium along a predetermined axis.   
     
     
       24. The process of claim 23, further said printer comprising a home sensor for sensing movement of said carriage along said predetermined axis, said home sensor including a base portion, a light emitting portion and a light receiving portion extending in parallel from said base portion, said light emitting portion emitting a light to be received by said light receiving portion to determine whether one of said first sensing rib and said second sensing rib separately mounted on said carriage passes through said light emitting portion.